| Message ID | 20180220033844.13999-1-chandan@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Tuesday, February 20, 2018 9:08:44 AM IST Chandan Rajendra wrote: > generic/388 can cause the following "use after free" error to occur, > > ============================================================================= > BUG xfs_efi_item (Not tainted): Poison overwritten > ----------------------------------------------------------------------------- > > Disabling lock debugging due to kernel taint > INFO: 0x00000000292c4bd4-0x00000000292c4bd4. First byte 0x6a instead of 0x6b > INFO: Allocated in .kmem_zone_alloc+0xcc/0x190 age=79 cpu=0 pid=12436 > .__slab_alloc+0x54/0x80 > .kmem_cache_alloc+0x124/0x350 > .kmem_zone_alloc+0xcc/0x190 > .xfs_efi_init+0x48/0xf0 > .xfs_extent_free_create_intent+0x40/0x130 > .xfs_defer_intake_work+0x74/0x1e0 > .xfs_defer_finish+0xac/0x5c0 > .xfs_itruncate_extents+0x170/0x590 > .xfs_inactive_truncate+0xcc/0x170 > .xfs_inactive+0x1d8/0x2f0 > .xfs_fs_destroy_inode+0xe4/0x3d0 > .destroy_inode+0x68/0xb0 > .do_unlinkat+0x1e8/0x390 > system_call+0x58/0x6c > INFO: Freed in .xfs_efi_item_free+0x44/0x80 age=79 cpu=0 pid=12436 > .kmem_cache_free+0x120/0x2b0 > .xfs_efi_item_free+0x44/0x80 > .xfs_trans_free_items+0xd4/0x130 > .__xfs_trans_commit+0xd0/0x350 > .xfs_trans_roll+0x4c/0x90 > .xfs_defer_trans_roll+0xa4/0x2b0 > .xfs_defer_finish+0xb8/0x5c0 > .xfs_itruncate_extents+0x170/0x590 > .xfs_inactive_truncate+0xcc/0x170 > .xfs_inactive+0x1d8/0x2f0 > .xfs_fs_destroy_inode+0xe4/0x3d0 > .destroy_inode+0x68/0xb0 > .do_unlinkat+0x1e8/0x390 > system_call+0x58/0x6c > > This happens due to the following interaction, > 1. xfs_defer_finish() creates "extent free" intent item and adds it to the > per-transction list of log items. > 2. xfs_defer_trans_roll() invokes __xfs_trans_commit(). Here, if the > XFS_MOUNT_FS_SHUTDOWN flag is set, we invoke io_unlock() operation > for each of the log items in the per-transction list. For "extent > free" log items xfs_efi_item_unlock() gets invoked which then frees > the xfs_efi_log_item. > 3. xfs_defer_trans_roll() then invokes xfs_defer_trans_abort(). Since the > xfs_defer_pending->dfp_intent is still set to the "extent free" intent > item, we invoke xfs_extent_free_abort_intent(). This accesses the > previously freed xfs_efi_log_item to decrement the ref count. > > This commit fixes the bug by invoking xfs_defer_trans_abort() only when > the log items in the per-transaction list have been committed to the > CIL. The log item "committed" status is being tracked by > xfs_defer_ops->dop_committed. This was the behaviour prior to commit > 3ab78df2a59a485f479d26852a060acfd8c4ecd7 (xfs: rework xfs_bmap_free > callers to use xfs_defer_ops). > > Reported-by: Christoph Hellwig <hch@lst.de> > Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> > --- > fs/xfs/libxfs/xfs_defer.c | 6 +++--- > fs/xfs/xfs_bmap_util.c | 2 +- > fs/xfs/xfs_inode.c | 2 +- > fs/xfs/xfs_trans.c | 8 +++++++- > fs/xfs/xfs_trans.h | 2 +- > fs/xfs/xfs_trans_inode.c | 2 +- > 6 files changed, 14 insertions(+), 8 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c > index 087fea0..eb879a0 100644 > --- a/fs/xfs/libxfs/xfs_defer.c > +++ b/fs/xfs/libxfs/xfs_defer.c > @@ -256,13 +256,13 @@ xfs_defer_trans_roll( > trace_xfs_defer_trans_roll((*tp)->t_mountp, dop); > > /* Roll the transaction. */ > - error = xfs_trans_roll(tp); > + error = xfs_trans_roll(tp, &dop->dop_committed); > if (error) { > trace_xfs_defer_trans_roll_error((*tp)->t_mountp, dop, error); > - xfs_defer_trans_abort(*tp, dop, error); > + if (dop->dop_committed == true) > + xfs_defer_trans_abort(*tp, dop, error); > return error; > } > - dop->dop_committed = true; > > /* Rejoin the joined inodes. */ > for (i = 0; i < XFS_DEFER_OPS_NR_INODES && dop->dop_inodes[i]; i++) > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > index c83f549..9d84d36 100644 > --- a/fs/xfs/xfs_bmap_util.c > +++ b/fs/xfs/xfs_bmap_util.c > @@ -1830,7 +1830,7 @@ xfs_swap_change_owner( > if (error != -EAGAIN) > break; > > - error = xfs_trans_roll(tpp); > + error = xfs_trans_roll(tpp, NULL); > if (error) > break; > tp = *tpp; > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > index 604ee38..6419549 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -1049,7 +1049,7 @@ xfs_dir_ialloc( > tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY); > } > > - code = xfs_trans_roll(&tp); > + code = xfs_trans_roll(&tp, NULL); > if (committed != NULL) > *committed = 1; I noticed that xfs_dir_ialloc() gets a "committed" argument passed to it. I think I can pass this on to xfs_trans_roll() instead of the NULL pointer. I will read up the code and decide on the next action.
diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c index 087fea0..eb879a0 100644 --- a/fs/xfs/libxfs/xfs_defer.c +++ b/fs/xfs/libxfs/xfs_defer.c @@ -256,13 +256,13 @@ xfs_defer_trans_roll( trace_xfs_defer_trans_roll((*tp)->t_mountp, dop); /* Roll the transaction. */ - error = xfs_trans_roll(tp); + error = xfs_trans_roll(tp, &dop->dop_committed); if (error) { trace_xfs_defer_trans_roll_error((*tp)->t_mountp, dop, error); - xfs_defer_trans_abort(*tp, dop, error); + if (dop->dop_committed == true) + xfs_defer_trans_abort(*tp, dop, error); return error; } - dop->dop_committed = true; /* Rejoin the joined inodes. */ for (i = 0; i < XFS_DEFER_OPS_NR_INODES && dop->dop_inodes[i]; i++) diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index c83f549..9d84d36 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1830,7 +1830,7 @@ xfs_swap_change_owner( if (error != -EAGAIN) break; - error = xfs_trans_roll(tpp); + error = xfs_trans_roll(tpp, NULL); if (error) break; tp = *tpp; diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 604ee38..6419549 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1049,7 +1049,7 @@ xfs_dir_ialloc( tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY); } - code = xfs_trans_roll(&tp); + code = xfs_trans_roll(&tp, NULL); if (committed != NULL) *committed = 1; diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c index 86f92df..1bf2505 100644 --- a/fs/xfs/xfs_trans.c +++ b/fs/xfs/xfs_trans.c @@ -1057,12 +1057,15 @@ xfs_trans_cancel( */ int xfs_trans_roll( - struct xfs_trans **tpp) + struct xfs_trans **tpp, + bool *committed) { struct xfs_trans *trans = *tpp; struct xfs_trans_res tres; int error; + if (committed) + *committed = false; /* * Copy the critical parameters from one trans to the next. */ @@ -1082,6 +1085,9 @@ xfs_trans_roll( if (error) return error; + if (committed) + *committed = true; + /* * Reserve space in the log for the next transaction. * This also pushes items in the "AIL", the list of logged items, diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h index 9d542df..d4deb49 100644 --- a/fs/xfs/xfs_trans.h +++ b/fs/xfs/xfs_trans.h @@ -230,7 +230,7 @@ int xfs_trans_free_extent(struct xfs_trans *, struct xfs_efd_log_item *, xfs_fsblock_t, xfs_extlen_t, struct xfs_owner_info *); int xfs_trans_commit(struct xfs_trans *); -int xfs_trans_roll(struct xfs_trans **); +int xfs_trans_roll(struct xfs_trans **, bool *); int xfs_trans_roll_inode(struct xfs_trans **, struct xfs_inode *); void xfs_trans_cancel(xfs_trans_t *); int xfs_trans_ail_init(struct xfs_mount *); diff --git a/fs/xfs/xfs_trans_inode.c b/fs/xfs/xfs_trans_inode.c index 4a89da4..bedd5fd 100644 --- a/fs/xfs/xfs_trans_inode.c +++ b/fs/xfs/xfs_trans_inode.c @@ -147,7 +147,7 @@ xfs_trans_roll_inode( int error; xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE); - error = xfs_trans_roll(tpp); + error = xfs_trans_roll(tpp, NULL); if (!error) xfs_trans_ijoin(*tpp, ip, 0); return error;
generic/388 can cause the following "use after free" error to occur, ============================================================================= BUG xfs_efi_item (Not tainted): Poison overwritten ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: 0x00000000292c4bd4-0x00000000292c4bd4. First byte 0x6a instead of 0x6b INFO: Allocated in .kmem_zone_alloc+0xcc/0x190 age=79 cpu=0 pid=12436 .__slab_alloc+0x54/0x80 .kmem_cache_alloc+0x124/0x350 .kmem_zone_alloc+0xcc/0x190 .xfs_efi_init+0x48/0xf0 .xfs_extent_free_create_intent+0x40/0x130 .xfs_defer_intake_work+0x74/0x1e0 .xfs_defer_finish+0xac/0x5c0 .xfs_itruncate_extents+0x170/0x590 .xfs_inactive_truncate+0xcc/0x170 .xfs_inactive+0x1d8/0x2f0 .xfs_fs_destroy_inode+0xe4/0x3d0 .destroy_inode+0x68/0xb0 .do_unlinkat+0x1e8/0x390 system_call+0x58/0x6c INFO: Freed in .xfs_efi_item_free+0x44/0x80 age=79 cpu=0 pid=12436 .kmem_cache_free+0x120/0x2b0 .xfs_efi_item_free+0x44/0x80 .xfs_trans_free_items+0xd4/0x130 .__xfs_trans_commit+0xd0/0x350 .xfs_trans_roll+0x4c/0x90 .xfs_defer_trans_roll+0xa4/0x2b0 .xfs_defer_finish+0xb8/0x5c0 .xfs_itruncate_extents+0x170/0x590 .xfs_inactive_truncate+0xcc/0x170 .xfs_inactive+0x1d8/0x2f0 .xfs_fs_destroy_inode+0xe4/0x3d0 .destroy_inode+0x68/0xb0 .do_unlinkat+0x1e8/0x390 system_call+0x58/0x6c This happens due to the following interaction, 1. xfs_defer_finish() creates "extent free" intent item and adds it to the per-transction list of log items. 2. xfs_defer_trans_roll() invokes __xfs_trans_commit(). Here, if the XFS_MOUNT_FS_SHUTDOWN flag is set, we invoke io_unlock() operation for each of the log items in the per-transction list. For "extent free" log items xfs_efi_item_unlock() gets invoked which then frees the xfs_efi_log_item. 3. xfs_defer_trans_roll() then invokes xfs_defer_trans_abort(). Since the xfs_defer_pending->dfp_intent is still set to the "extent free" intent item, we invoke xfs_extent_free_abort_intent(). This accesses the previously freed xfs_efi_log_item to decrement the ref count. This commit fixes the bug by invoking xfs_defer_trans_abort() only when the log items in the per-transaction list have been committed to the CIL. The log item "committed" status is being tracked by xfs_defer_ops->dop_committed. This was the behaviour prior to commit 3ab78df2a59a485f479d26852a060acfd8c4ecd7 (xfs: rework xfs_bmap_free callers to use xfs_defer_ops). Reported-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> --- fs/xfs/libxfs/xfs_defer.c | 6 +++--- fs/xfs/xfs_bmap_util.c | 2 +- fs/xfs/xfs_inode.c | 2 +- fs/xfs/xfs_trans.c | 8 +++++++- fs/xfs/xfs_trans.h | 2 +- fs/xfs/xfs_trans_inode.c | 2 +- 6 files changed, 14 insertions(+), 8 deletions(-)